Here is a list of projects in maths, not great for the science Investigation but very good for SCI-fest
A site that I found recently and is home to some proper projects, ones that have something that can be measured.
for those interested in plants and science projects to do with them
The latest science fair website that I have found comes from the people that bring you the Discovery Channel http://school.discoveryeducation.com/sciencefaircentral/
It is a very complete site, especially for those wanting to do a Young Scientist or Scifest expt.
I found this link and its quite interesting,
Quite probably a very important place to start looking for your investigation title, follow the links
A Link to another page like this in America, the other site is a little better :(
On this page you will find more links to other pages that have lists of projects
Mad Science presents
Some ideas that Intel thought up
You may find a range of chemistry Ideas here
Check the Virtual Gallery
A load of projects with back up from Hilaroad.com
More in the way of chemistry projects
More from the same
A new resource of about 20 experiments, some are good ...
A few more experiments here
If you are interested in Plant Biology then this page will give you some ideas
Lots of Young Scientist Ideas
Steve Spangler does science
A Science shop with lots of DIY experiments too
Hints & Tips for doing well at a science fair (Young Scientist)
A few more experiments